A sufficient number of copies of each purchase order issued should be made so that the accounting department may receive a copy, and that there may be a copy for the purchase order file, and in addition the receiving authority should have a copy for his information. Voucher checks are popular and highly desirable for items of this character. Such checks contain either on a fly sheet or on one side, the date and amount of the bills which they cover. All bills should be adequately checked with the purchase order copies and invoices and should be properly approved before payment. Postings to the supply card record are made from purchase orders and requisitions for supplies.